Monthly Archives: October 2012

Mold making Beachstones 2

 

47_beachstonemoldThe silicone trimmed-off.

 

 

 

 

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The first half mold finished. Plaster mother mold and silicone mold together.

 

 

 

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Next half begins. Again, apply a clay blanket 1/4 to 3/8 inch thick to exposed object and mold. Remember, the clay will eventually become the shape of the poured silicone later. I carved some half-round indents onto the plaster in each corner to create an interlock with the 2nd half.

51_beachstonemoldThe two molds ready for the 2nd half plaster mother mold to happen.

 

 

 

52_beachstonemoldReady for plaster to be poured; each mold boxed, with a pour sprue for the silicone. Seal edges of mold along the sides of the box to prevent leakage. Apply spray-on mold release liberally everywhere.

 

53_beachstonemoldMarks on the tube show how deep to pour the plaster. One inch is enough. Light weight is better.

 

 

 

55_beachstonemoldPoured OK. Allow to dry at least 48 hours. Plaster continues to harden for days.

 

 

 

56_beachstonemoldRemove the box and tube, open the mold carefully using fine wooden wedges. Don’t force it.

 

 

 

58_beachstonemoldRemove the clay blanket, you’re done with it. Wax the whole surface of the plaster with Briwax, and spray release on it and the first side, and model, &c.

 

 

59_beachstonemoldReassemble the molds, ready for casting the silicone. Seal the funnel sprue area with clay.

 

 

 

61_beachstonemoldThe silicone poured. See the clay seals around the sprue required to keep the silicone in the mold.

 

 

 

64_beachstonemoldCure silicone 24-48 hours, and open the plaster mold. Trim off any over bleed.

 

 

 

67_beachstonemoldOpen the silicone mold.

 

 

 

 

69_beachstonemoldRemove the model. Nice. This is what it’s all been for.

 

 

 

 

72_beachstonemoldReassembled molds, ready to be poured with wax, plastic, or cement.

 

 

 

This whole 2nd half mold was another 6 sessions of work, about 4-6 hours each, or about three weeks of weekends and nights after work. My October, Happy. These are two good molds and now I hope to get some good product out of them.

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